In automated processes, such as in the automotive industry, nuts may be welded to body components, such as formed mild steel sheet members, prior to assembly. The nuts are typically welded to the sheet at specified locations. The head of the welding electrode has a limited life, for many reasons. Typically, the electrode tip is made of copper or a copper alloy, and is consumed over time, as the repeated heating and cooling of the tip degrades the tip. Where the nuts are fed to the welding electrode heads automatically, it is not desirable to weld the nuts in the wrong location or upside down.